The present invention relates to a golf ball having a surface formed of numerous recessed dimples. More specifically, the invention relates to a golf ball which, by lowering fluctuations in lift and drag at high and low spin rates, is thus able to achieve a stable trajectory.
With recent advances in golfing equipment such as balls and clubs, it is not unusual for golf balls to be struck under low-spin conditions. However, depending on differences between golfers in the spin rate of a ball struck with a driver, substantial disparities in the distance traveled sometimes arise. To the amateur golfer in particular, because hitting the ball with a driver under low-spin conditions remains a challenge, the outcome is inconsistent—the ball will travel well at times and travel poorly at other times. In addition, when golfing, one has to deal constantly with wind conditions such tailwinds and headwinds. Accordingly, there exists a desire for the development of golf balls which minimize differences in flight performance under such conditions and increase a player's sense of stability.
A variety of golf balls have already been disclosed which, by optimizing the dimples on the surface of the ball, lower the flight trajectory and hold down decreases in distance.
For example, JP-A 05-103846 describes a golf ball in which the dimple diameter, dimple depth and number of dimples have been optimized. JP-A 10-043342 and JP-A 10-043343 disclose golf balls in which the amount of deformation by a ball when subjected to a load of 100 kg has been set to an appropriate value, the dimple diameter divided by the dimple depth has been set to from 10 to 15, and the dimple space volume as a proportion of the total volume of a hypothetical sphere were the ball to have no dimples on the surface thereof has been set to from 0.7 to 1.1%. JP-A 2000-107338 discloses a practice golf ball in which the ball weight and diameter have been optimized.
However, in the foregoing prior-art golf balls, the dimples have been optimized only for relatively high-spin conditions; the ball trajectory at low spin rates has been less than satisfactory.
It is therefore an object of the present invention to provide a golf ball which, by lowering fluctuations in lift and drag at high and low spin rates, is able to achieve a stable trajectory.